Investigation On Gashydrate In Permafrost Using Remote Sensing Technique

Through a full investigation on literature about gas hydrate, especiallyterrestrial gas hydrate, including geological background of reservoir formation andapplication of exploration technology, it is discussed the possibility of using remotesensing technique to explore relative information about gas hydrate in permafrostarea, as well as its material basis. Based on the model of reservoir formation andreservoir properties, it is improved and developed the techniques using remotesensing to extract information about temperature and pressure in permafrost area andsurvey source of materials, providing an effective method of fast exploration for gashydrate in permafrost area. Gas hydrate and petroleum geology in the Tibetanplateau have certain spatio-temporal coupling relationship. Taken area along theQinghai-Tibet Railway as an example, MODIS and ASTER data are used to inversethe temperature and pressure of gas hydrate reservoir formation, distribution ofmaterial sources, associated alteration information and so on along the Qinghai-TibetRailway. Finally, through a comprehensive analysis, it is discussed the generalsituation of possible and potential occurrence of gas hydrate along the Qinghai-TibetRailway. Main results are as follows:1. Through wide investigation on literature about gas hydrate, especiallyterrestrial gas hydrate, it is fully analyzed geological, geographical conditions, suchas reservoir formation model and formation conditions, and surveying techniques,providing basic, comparable investigation report with complete documents forexploration and development of gas hydrate in terrestrial permafrost area.2. Based on analysis about reservoir model and reservoir conditions of gashydrate, taken into account spectral characteristics of rock and mineral, as well as thefeatures of ASTER data, it is improved the ratio/differential advancement method forlithologic information, to identify mineral types by the waveband features of ASTERdata;it is developed an information analysis method reflecting associated alterationeffects by spectral cooperation of visible-thermal infrared spectral range. It isidentified and obtained the distribution of some mineral types related to gas hydratealong the Qinghai-Tibet Railway, advanced some rock types, extracted and analyzedpossible existing clayization of feldspar group in the region. These multi-aspectresults provide a lot of basic information about material source and surface alterationfor gas hydrate exploration.3. It is obtained, using MODIS data, terrestrial surface temperature and annualaverage ground temperature along the Qinghai-Tibet Railway, circled permafrostzones, classified frozen ground types and inversed frozen ground depth. Thesesresults provide necessary, important pressure and temperature constraints forcomprehensive analysis on forming, accumulating and preserving of gas hydrate intested region.4. Through complete analysis on oil and gas reservoir formation, plateau uplift,frozen ground formation, glacier transgression and regression, it is believed thatthere exists a certain spatio-temporal coupling relationship between gas hydratereservoir accumulation and preserving conditions, etc.5. Combined with literature investigation, spatio-temporal coupling relationshipof gas hydrate in the Tibetan plateau, field survey and examining work, results ofremote sensing exploration using MODIS and ASTER data along the Qinghai-TibetRailway, it is analyzed the general situation of possible, potential occurrence of gashydrate along the Qinghai-Tibet Railway, including gas hydrate controlling factors,sources of material, hydrocarbon weak seepage and associated alteration effects, etc.